The suitability of various rubbers for certain specific applications can be improved by blending syndiotactic 1,2-polybutadiene (SPBD) with the rubber. For instance, SPBD fibers can be utilized as a tread base rubber in tires in order to improve their heat build-up and wear characteristics. For example, U.S. Pat. No. 4,274,462 discloses pneumatic tires having improved resistance against heat build-up which employ SPBD fibers in their tread base rubber. It has also been determined that SPBD can be blended into tire carcass formulations in order to improve the green strength thereof. In fact, the inclusion of SPBD in tire carcass formulations can eliminate the need for electron beam precure in tire building operations.
The interaction and adhesion of SPBD with rubbers and fillers, such as carbon black, can be improved by carboxylating the SPBD. As a general rule, it is highly desirable to increase the interaction between the SPBD and the rubber/filler. For this reason a means for carboxylating SPBD has been sought. Unfortunately, standard techniques for carboxylating organic materials have not led to the incorporation of significant amounts of carboxylic acid groups onto SPBD. For instance, the treatment of SPBD with sulfuric acid and formic acid has not resulted in appreciable incorporation of carboxylic acid groups onto SPBD.